Fixed crashing bug, final check before submit

[Schleimer, Ben]

--- Boudewijn Rempt <boud at valdyas.org> wrote:

> 
> But that's right: if you use "convert image" layers are converted to, and if 
> you image properties layers are not converted. I guess the menu entry name is 
> unfortunate: we can fix that for trunk.
> 

Ok, I give up on changing the properties dialog in the layerbox. I jut submitted some small
changes for const correctness (it breaks binary-compatibility for colorspaces) and the colorspace
pointer comparsion.

Cheers
Ben